This disclosure relates to a continuous miner, and, more particularly, to a discharge boom of a continuous miner.
A variety of methods exist for mining coal and other materials from underground seams. One apparatus that is commonly employed in underground mining operations comprises a continuous mining machine that includes a rotatable cutting drum that is mounted on the front end of the mining machine. As the mining machine is advanced into the seam, the cutting drum dislodges or “wins” the coal from the seam. In some continuous miners of this type, the won material is conveyed rearwardly of the cutter drum by a longitudinally extending conveyor that may discharge into shuttle cars or other mobile conveying apparatuses to transport the won material from the mine face. The continuous mining machine continuously advances into the seam and, as the material is won there from, an entry or tunnel is formed in the seam.
More particularly, as shown in FIGS. 1 and 2 from US Bennett et al U.S. Pat. No. 3,516,712, a continuous miner is supported on endless traction treads 11 and 12, which are at opposite sides thereof, on which the machine is propelled. At the forward end of the mining machine 10 there is a rotary mining head 13, on a transverse axis, to be advanced or sumped into the mine face 14. The mining head 13 is supported on the forward end of a boom 15 by which it may be raised to the roof 16, sumped into the material of the mine face 14, and traversed through the material downwardly to the floor 17. The mining head 13 extends transversely between the opposite ribs 18, 19, and the latter define the side boundaries of the face area that is mined by the mining head 13.
The mining head 13 is supported on the boom 15 at the forward end of the mining machine 10, for rotation of the mining head 13 about its transversely disposed axis. The boom 15 is connected to a mining machine main frame 20 on transverse pivots 21, 22 on which the boom 15 is swung upwardly and downwardly by cylinders 23, 24, connected between the main frame 20 and the boom 15.
Motors 25, 26, power the mining machine 10 on opposite sides of the boom 15. Driving connections 27, 28 extend forwardly from motors 25, 26, respectively, to transmissions 29, 30, at opposite sides of the boom 15, from which the mining head 13 is driven. The motors 25, 26 also provide power for driving traction treads 11, 12. Drive connections 31, 32 extend rearwardly from motors 25, 26, respectively, to transmissions 33, 34 at opposite sides of the main frame 20 for delivering the drive to the traction treads 11, 12.
In the mining operation the material cut and broken out of the mine face 14 falls to the floor 17. There is a gathering head 35 at the front of the mining machine 10, below the boom 15. The gathering head 35 has an apron or deck 36 with its leading edge at the floor 17. Gathering arms 37, 38 at opposite sides of the gathering head 35 operate with an oscillating motion to reach down and to sweep the material into a conveyor 39 that extends longitudinally through the mining machine 10 from the gathering head 35 to a discharge boom 40 at the rear end of the mining machine 10. The conveyor 39 moves the mined material from the forward end of mining machine 10 to its rear end at which it is discharged to conveying apparatus for removing the mined material from the mining place.
The motors 25, 26, power the gathering arms 37, 38. Driving connections 41, 42 extend forwardly from transmissions 33, 34, respectively, to gathering head transmissions 43, 44, from which the gathering arms 37, 38 are driven.
Underground mining utilizes steel-flight conveyor chains to move the mined material along the conveyor 39 from the cutting-end of the continuous miner to a tail or rear end of the discharge boom 40. These conveyor chains move at high speed and ride in steel fabricated troughs. The conveyor chain “flights” engage the mined material and slide it along within these troughs until it reaches the tail end of the conveyor where it is discharged.
One of the highest noise-generating areas of a continuous miner is in the pivoting boom 40 of the machine 10. Here, there are multiple location where conveyor chain “impacts” occur at the tail roller, take-up slide plate, take-up mechanism, springs, struts, cam & follower, pivots, flex-boards, etc. The steel conveyor chains sliding on, and passing over, steel joints, rollers, and guides create numerous impact locations that cause very high sound decibel levels.